01 /*
02 * Copyright 2008-2015 the original author or authors.
03 *
04 * Licensed under the Apache License, Version 2.0 (the "License");
05 * you may not use this file except in compliance with the License.
06 * You may obtain a copy of the License at
07 *
08 * http://www.apache.org/licenses/LICENSE-2.0
09 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package griffon.transform;
17
18 import org.codehaus.groovy.transform.GroovyASTTransformationClass;
19
20 import java.lang.annotation.ElementType;
21 import java.lang.annotation.Retention;
22 import java.lang.annotation.RetentionPolicy;
23 import java.lang.annotation.Target;
24
25 /**
26 * <p>Annotates a property.</p>
27 * <p>This transformation provides a convenient way to register PropertyChangeListeners
28 * on an observable bean by leveraging Groovy's closures and the Groovy cast operator.</p>
29 * <p/>
30 * <p>The following code exemplifies what must be written by hand in order to register a pair
31 * of PropertyChangeListeners. One of them is a catch-all handler while the second is property specific.
32 * <pre>
33 * import griffon.transform.Observable
34 * import java.beans.PropertyChangeListener
35 *
36 * class MyModel {
37 * @Observable String name
38 * @Observable String lastname
39 *
40 * def snoopAll = { evt -> ... }
41 *
42 * MyModel() {
43 * addPropertyChangeListener(snoopAll as PropertyChangeListener)
44 * addPropertyChangeListener('lastname', {
45 * controller.someAction(it)
46 * } as PropertyChangeListener)
47 * }
48 * }
49 * </pre>
50 * <p/>
51 * <p>Applying @PropertyListener to the previous snippet results in the following code</p>
52 * <pre>
53 * import griffon.transform.PropertyListener
54 * import griffon.transform.Observable
55 *
56 * @PropertyListener(snoopAll)
57 * class MyModel {
58 * @Observable String name
59 *
60 * @Observable
61 * @PropertyListener({controller.someAction(it)})
62 * String lastname
63 *
64 * def snoopAll = { evt -> ... }
65 * }
66 * </pre>
67 * <p/>
68 * Any closures found as the annotation's value will be either transformed
69 * into inner classes that implement PropertyChangeListener (when the value
70 * is a closure defined in place) or be casted as a proxy of PropertyChangeListener
71 * (when the value is a property reference found in the same class).<p>
72 * List of closures are also supported.
73 *
74 * @author Andres Almiray
75 */
76 @Retention(RetentionPolicy.SOURCE)
77 @Target({ElementType.FIELD, ElementType.TYPE})
78 @GroovyASTTransformationClass("org.codehaus.griffon.compile.core.ast.transform.PropertyListenerASTTransformation")
79 public @interface PropertyListener {
80 String value();
81 }
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